1 材料与方法
1.1 伦理声明
1.2 试验设计和试验饲料
表1 试验饲料组成及营养水平(干物质基础)Table 1 Composition and nutrient levels of experimental diets (DM basis) |
| 项目 Items | 组别 Groups | ||
|---|---|---|---|
| CON | LL | HL | |
| 原料 Ingredients | |||
| 秘鲁鱼粉 Peru fish meal | 50.00 | 50.00 | 50.00 |
| 大豆浓缩蛋白 Soy protein concentrate | 13.00 | 13.00 | 13.00 |
| 豆粕 Soybean meal | 10.00 | 10.00 | 10.00 |
| 面粉 Wheat flour | 7.00 | 7.00 | 7.00 |
| 鱼油 Fish oil | 3.00 | 7.00 | |
| 豆油 Soybean oil | 3.00 | 7.00 | |
| 维生素预混料 Vitamin premix1) | 0.75 | 0.75 | 0.75 |
| 矿物质预混料 Mineral premix2) | 0.75 | 0.75 | 0.75 |
| 维生素C Vitamin C | 0.20 | 0.20 | 0.20 |
| 磷酸二氢钙 Ca(H2PO4)2 | 1.50 | 1.50 | 1.50 |
| 羧甲基纤维素钠 Sodium carboxymethyl cellulose | 1.00 | 1.00 | 1.00 |
| 微晶纤维素 Microcrystalline cellulose | 9.80 | 15.80 | 1.80 |
| 合计 Total | 100.00 | 100.00 | 100.00 |
| 营养水平 Nutrient levels3) | |||
| 粗蛋白质 CP | 46.67 | 46.42 | 46.55 |
| 粗脂肪 EE | 10.36 | 4.15 | 18.23 |
1)每千克维生素预混料含有 One kilogram of vitamin premix contained the following: VA 800 000 IU,VD3 200 000 IU,VE 5 000 mg,VK3 500 mg,VB1 800 mg,VB2 800 mg,VB6 800 mg,VB12 20 mg,烟酰胺 nicotinamide 5 000 mg,D-泛酸钙 D-calcium pantothenate 2 800 mg,叶酸 folic acid 250 mg,D-生物素 D-biotin 8 mg,肌醇 inositol 65 000 mg。 | |
2)每千克矿物质预混料含有 One kilogram of mineral premix contained the following: Cu (CuSO4) 450 mg,Zn (ZnSO4) 1 800 mg,Mn (MnSO4) 1 500 mg,Fe (FeSO4) 1 500 mg,I (Ca (IO3)2) 65 mg,Se (Na2SeO3) 15 mg,Co (CoCl2) 50 mg,Mg (MgSO4·H2O) 4 000 mg。 3)营养水平为实测值。Nutrient levels were measured values. |
1.3 饲养管理
1.4 样本采集
1.5 指标测定
1.5.1 生长性能
1.5.2 饲粮营养水平和全鱼体成分
1.5.3 血清生化指标
1.5.4 肠道抗氧化指标
1.5.5 肠道凋亡和炎症相关基因表达
表2 实时荧光定量PCR引物序列Table 2 Primer sequences for quantitative real-time PCR |
| 基因 Genes | 正向引物 Forward primer (5'—3') | 反向引物 Reverse primer (5'—3') |
|---|---|---|
| 白细胞介素-1β IL-1β | CGTGACTGACAGCAAAAAGAGG | GATGCCCAGAGCCACAGTTC |
| 白细胞介素-8 IL-8 | CGTTGAACAGACTGGGAGAGATG | AGTGGGATGGCTTCATTATCTTGT |
| 核因子-κB NF-κB | ACTCATGTTCACGGCGTTCCT | TCTTCAGGTTGGAGGCGTTGG |
| 白细胞介素-10 IL-10 | CGGCACAGAAATCCCAGAGC | CAGCAGGCTCACAAAATAAACATCT |
| 转化生长因子-β TGF-β | TGTCGTCCGTGTTCTCCTCAC | GTAAATGGCGACAATCTCACG |
| 半胱天冬酶9 Caspase9 | CTGGAATGCCTTCAGGAGACGGG | GGGAGGGGCAAGACAACAGGGTG |
| B细胞淋巴瘤-2相关X蛋白 Bax | GCTTGTCACCACAGCCATTG | TACAGCAGACCAGCACAAGG |
| B细胞淋巴瘤-2 Bcl-2 | CCAACGTCATGGTTGTCATGG | GTGGAGCCAACCAGGAATCT |
| 半胱天冬酶3 Caspase3 | CACGGTGATGAGGGTGTGTT | CCAGATCAGTGCCTCTGCAA |
| β-肌动蛋白 β-actin | CTCTGCATACATGCCTACAC | GTAGAGTTTCTCCCCATCAGG |
1.5.6 肠道菌群16S rRNA测序
1.6 数据统计分析
2 结果与分析
2.1 饲料中过高或过低的脂肪水平对大口黑鲈生长性能的影响
表3 饲料中过高或过低的脂肪水平对大口黑鲈生长性能的影响Table 3 Effects of dietary excessively high or low fat levels on growth performance of largemouth bass |
| 项目 Items | 组别 Groups | ||
|---|---|---|---|
| CON | LL | HL | |
| 初始体重 IBW/g | 2.69±0.02 | 2.70±0.00 | 2.67±0.02 |
| 终末体重 FBW/g | 29.69±0.61b | 25.43±1.39a | 25.00±0.94a |
| 增重率 WGR/% | 1 005.72±24.07b | 841.73±51.18a | 837.35±32.37a |
| 特定生长率 SGR/(%/d) | 4.30±0.04b | 4.00±0.10a | 3.98±0.06a |
| 肥满度 CF/(g/cm3) | 2.39±0.18 | 2.42±0.10 | 2.30±0.13 |
| 肝体比 HSI/% | 0.91±0.04 | 0.91±0.04 | 0.96±0.08 |
| 脏体比 VSI/% | 7.09±0.20b | 6.07±0.17a | 7.84±0.03c |
| 摄食量 FI/g | 33.10±0.58 | 29.54±0.35 | 29.37±0.46 |
| 饲料系数 FCR | 1.21±0.01a | 1.35±0.03b | 1.39±0.04b |
| 成活率 SR/% | 100.00±0.00 | 100.00±0.00 | 100.00±0.00 |
同行数据肩标不同小写字母表示差异显著(P<0.05),相同或无字母表示差异不显著(P>0.05)。下表同。 | |
In the same row, values with different small letter superscripts mean significant difference (P<0.05), while with the same or no letter superscripts mean no significant difference (P>0.05). The same as below. |
2.2 饲料中过高或过低的脂肪水平对大口黑鲈全鱼营养成分的影响
表4 饲料中过高或过低的脂肪水平对大口黑鲈全鱼营养成分的影响Table 4 Effects of dietary excessively high or low fat levels on whole fish nutritional composition of largemouth bass |
| 项目 Items | 组别 Groups | ||
|---|---|---|---|
| CON | LL | HL | |
| 水分 Moisture | 72.35±1.43b | 74.74±0.41b | 69.69±0.12a |
| 粗蛋白质 CP | 16.04±0.42 | 16.11±0.20 | 15.90±0.21 |
| 粗脂肪 EE | 7.34±0.06b | 6.22±0.16a | 10.86±0.35c |
2.3 饲料中过高或过低的脂肪水平对大口黑鲈血清生化指标的影响
表5 饲料中过高或过低的脂肪水平对大口黑鲈血清生化指标的影响Table 5 Effects of dietary excessively high or low fat levels on serum biochemical indexes of largemouth bassm |
| 项目 Items | 组别 Groups | ||
|---|---|---|---|
| CON | LL | HL | |
| 总胆固醇 TC | 5.87±0.38a | 5.08±0.28a | 8.15±0.55b |
| 低密度脂蛋白胆固醇 LDL-C | 4.24±0.22b | 2.65±0.11a | 5.20±0.22c |
| 高密度脂蛋白胆固醇 HDL-C | 5.52±0.73 | 3.69±0.16 | 4.41±0.54 |
| 甘油三酯 TG | 11.29±0.42b | 8.10±0.39a | 14.66±0.41c |
2.4 饲料中过高或过低的脂肪水平对大口黑鲈肠道抗氧化指标的影响
表6 饲料中过高或过低的脂肪水平对大口黑鲈肠道抗氧化指标的影响Table 6 Effects of dietary excessively high or low fat levels on intestinal antioxidant indexes of largemouth bass |
| 项目 Items | 组别 Groups | ||
|---|---|---|---|
| CON | LL | HL | |
| 丙二醛 MDA/(nmol/mg prot) | 3.53±0.09a | 5.55±0.12b | 8.12±0.87c |
| 超氧化物歧化酶 SOD/(U/mg prot) | 88.19±1.30c | 70.09±0.66b | 60.78±1.24a |
| 过氧化氢酶 CAT/(U/g prot) | 9.20±0.47c | 5.75±0.37b | 3.52±0.16a |
2.5 饲料中过高或过低的脂肪水平对大口黑鲈肠道凋亡和炎症相关基因表达的影响
图1 饲料中过高或过低的脂肪水平对大口黑鲈肠道凋亡和炎症相关基因表达的影响Bcl-2:B细胞淋巴瘤-2 B-cell lymphoma-2;Bax:B细胞淋巴瘤-2相关X蛋白 B-cell lymphoma-2 associated X protein;Caspase3:半胱天冬酶3 cysteinyl aspartate proteinase 3;Caspase9:半胱天冬酶9 cysteinyl aspartate proteinase 9;TGF-β:转化生长因子-β transforming growth factor-β;IL-10:白细胞介素-10 interleukin-10;NF-κB:核因子-κB nuclear factor-κB;IL-8:白细胞介素-8 interleukin-8;IL-1β:白细胞介素-1β interleukin-1β。 数据柱标相同小写字母表示差异不显著(P>0.05),不同小写字母表示差异显著(P<0.05)。Value columns with the same small letter mean no significant difference (P>0.05), while with different small letters mean significant difference (P<0.05). Fig.1 Effects of dietary excessively high or low fat levels on expression of apoptosis- and inflammatory-related genes in intestine of largemouth bass |
2.6 饲料中过高或过低的脂肪水平对大口黑鲈肠道菌群的影响
表7 饲料中过高或过低的脂肪水平对大口黑鲈肠道菌群α多样性的影响Table 7 Effects of dietary excessively high or low fat levels on intestinal microbiota α diversity of largemouth bass |
| 项目 Items | 组别 Groups | ||
|---|---|---|---|
| CON | LL | HL | |
| OTU数量 OTU number | 520.50±30.31c | 436.00±21.94b | 306.50±8.95a |
| Chao1指数 Chao1 index | 581.00±28.61c | 496.50±26.56b | 396.50±9.53a |
| Ace指数 Ace index | 581.00±31.75b | 499.50±29.16b | 405.50±15.88a |
| Shannon指数 Shannon index | 2.81±0.12c | 1.89±0.22b | 0.87±0.08a |
| Simpson指数 Simpson index | 0.14±0.02a | 0.39±0.03b | 0.67±0.07c |
| 覆盖率 Coverage/% | 99.91±0.00 | 99.77±0.04 | 99.77±0.01 |
表8 饲料中过高或过低的脂肪水平对大口黑鲈肠道菌群门水平和属水平相对丰度的影响Table 8 Effects of dietary excessively high or low fat levels on relative abundances of intestinal microbiota at phylum level and genus level of largemouth bass |
| 项目 Items | 组别 Groups | ||
|---|---|---|---|
| CON | LL | HL | |
| 门水平 Phylum level | |||
| 厚壁菌门 Firmicutes | 38.17±2.60a | 78.72±5.29b | 92.32±1.38c |
| 变形菌门 Proteobacteria | 19.18±2.14b | 15.00±3.87b | 4.17±1.37a |
| 蓝细菌门 Cyanobacteria | 23.11±1.17b | 1.68±0.42a | 2.24±0.22a |
| 放线菌门 Actinobacteriota | 16.14±1.64b | 2.98±0.89a | 0.49±0.17a |
| 属水平 Genus level | |||
| 支原体属 Mycoplasma | 21.86±4.72a | 59.78±1.77b | 79.71±5.10c |
| norank_f_norank_o_Chloroplast | 23.11±1.17b | 1.61±0.38a | 2.24±0.22a |
| 葡萄球菌属 Staphylococcus | 3.82±0.08a | 14.63±4.35b | 0.07±0.02a |
| 雷夫松氏菌属 Leifsonia | 15.14±1.46b | 1.92±0.56a | 0.09±0.03a |
3 讨论
3.1 饲料中过高或过低的脂肪水平对大口黑鲈生长性能的影响
3.2 饲料中过高或过低的脂肪水平对大口黑鲈肠道抗氧化能力的影响
3.3 饲料中过高或过低的脂肪水平对大口黑鲈肠道炎症的影响
3.4 饲料中过高或过低的脂肪水平对大口黑鲈肠道细胞凋亡的影响
3.5 饲料中过高或过低的脂肪水平对大口黑鲈肠道菌群结构和组成的影响
图4 饲料中过高或过低脂肪水平影响大口黑鲈生长性能和肠道健康的可能作用机制WGR:增重率 weight gain rate;SGR:特定生长率 specific growth rate;FCR:饲料系数 feed conversion ratio;SOD:超氧化物歧化酶 superoxide dismutase;CAT:过氧化氢酶 catalase;MDA:丙二醛 malondialdehyde;IL-1β:白细胞介素-1β interleukin-1β;IL-8:白细胞介素-8 interleukin-8;NF-κB:核因子-κB nuclear factor-κB;IL-10:白细胞介素-10 interleukin-10;TGF-β:转化生长因子-β transforming growth factor-β;Caspase9:半胱天冬酶9 cysteine aspartate protease 9;Bax:B细胞淋巴瘤-2相关X蛋白 B-cell lymphoma-2 associated X protein;Caspase3:半胱天冬酶3 cysteine aspartate protease 3;α-div:α多样性alpha diversity;F:厚壁菌门 Firmicutes;M:支原体属 Mycoplasma。↑:升高 increase;↓:降低 decrease。 Fig.4 Potential mechanism of dietary excessively high or low fat levels affect growth performance and intestinal health of largemouth bass |

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